In a gas turbine engine designed for use in a helicopter application it is desirable to maintain rotor speed within a stable operating range. For example, if the rotor is attached to a low pressure turbine and if the rotor speed exceeds the stable operating range such that the turbine speed becomes excessive, then destructive conditions may occur. Alternatively, if the rotor speed falls below the stable operating range, then the helicopter will lose lift. Control of the rotor speed becomes difficult when the engine is used in an application, such as a helicopter, in which the operator may be frequently and rapidly changing the load on the engine such as by varying the collective pitch on the rotor. These load changes may result in a deviation from the desired rotor speed, typically termed "droop." Control systems are typically designed primarily for stability, and therefore the system s response to the droop is relatively slow to recuperate to the desired speed. In contrast, other control systems are designed for a relatively quick recuperation, however these systems are characterized as having low stability wherein the output of the system resonates resulting in undesirable torque disturbances. It is therefore desirable to have a control system for a gas turbine engine which provides quick recuperation in rotor speed without excessive instability.